Construction of ignition module: how to use and repair

Everyone knows that there are no unnecessary components in a car. All of them are meant for certain purpose. Ignition module is not an exception. This comparatively small mechanism, which is often called a coil, is main component of breakerless ignition system and is meant for high voltage production, due to which spark occurs on ignition plugs. This article deals with construction and operating principle of ignition module and also gives the information of its most typical failures and how to identify them.

1. Operating principle of ignition module

Considering that there are several ignition systems existing nowadays, it is logical that all of them have different modules. For example, separate modules provide one coil per each ignition plug and modular block provides one coil for two or all cylinders. In early days only one ignition coil was installed in all vehicles. Its energy was delivered to ignition plugs through distributive canal. But such systems were very unreliable. Because of that, electronic ignition was installed into vehicle.
In modern systems module performance is controlled by electronic control unit, which applies direct current to its windings. According to law of induction, high voltage is generated and directed to the plug.

The control unit generates a low-voltage control signal for the module, according to crankshaft position. The end of a signal is a beginning of ignition. Duration of the process is determined by state of coil charge and depends on car electrical system. The specific of module operation process is directing two sparks simultaneously: for one group it is directed while fuel-air mixture compression, for another – on outstroke (“no-load spark”). The “working” plugs are connected to the first and fourth cylinder (first coil operating zone) and “no-load” ones – to second and third cylinder (second coil operating zone).

2. Construction

The ignition module is submitted in a form of EC grade fair-sized construction, which gathers necessary electric current with voltage up to 30000W. Delivery of such high-voltage is performed through high voltage wires. The construction of ignition module combines two ignition coils, two igniters and high voltage wires outputs. Each coil is connected to cylinders: 1-st with first and fourth cylinder, 2-nd with second and third cylinder.

Such mechanism has no moving elements. This has a good impact on its working lifespan because module of ignition requires additional adjustments and it is controlled electronically (special controller manages the ignition system by reading out data from engine sensors). Electronic modules are more reliable and efficient and have a longer working life span. They fail rare and have high quality index.

3. Main failure types

Though the ignition module is highly reliable, sometimes it fails. As practice shows, the problems occur because of installation of the components with wrong parameters. For example, high voltage wires with too low or too high resistance can cause coil breakdown. It can only be fixed with full module replacement. Besides, correct type of ignition plugs plays no small part in module functioning, because large leash may cause failure of module as well as of other components.

The ignition system of today vehicle is truly reliable, but only if it repair and maintenance is performed by skilled technicians. Module ignition failure is a wide-spread reason of car breakdown. Because of it, you have to turn to service station experts. There are two types of ignition module failures: complete failure (no spark in plugs) of operating variables or fractional deflection from them (there is a spark in plugs).

In first case it is easy to identify the problem with the help of different methods and devices every automotive electrician has. The second case is more complicated. Unlike complete failure, you’ll be able to start engine with fractional defects and it will even work at idle. But load it a bit more and the problems become more obvious. Usually, module breakdown causes loss of ignition in two cylinders at once.

4. How to inspect the ignition module

It is quite possible to check module of ignition efficiency “at home”. There are different ways to do it. First, inspect the plugs. If there is a soot deposition on them, this is a result of weak spark, which can be seen with a naked eye (the spark will be of slightly blue color). The module resistance level between 1 and 4, 2 and 3 output also should be inspected. If the results are within normal range (5.5 – 6.5 kΩ) then the failure has been caused by second winding.

Besides, high voltage wire resistance can also affect module operation. Too high or low resistance is very unfavorable.

The easiest way of diagnosis is to replace broken module with intact one. After that, compare both results. Methods of module inspection mentioned above are not very complicated and can be performed everywhere if you have even standard tools.

5. Recommendations on exploitation of ignition modules

To ensure the module of a car lived long without failures, driver must follow its exploitation rules. Remember! Don’t live working ignition without engine started for a long time. This will impact ignition coils and lead to their breakdown. Also, check the condition of these components from time to time. You must clean the dead spots or replace worn details if necessary. Pay special attention to spark plug wires and body frame wholeness (there must be no moisture)